Very little emerges about the private lives of Russia's rich elite, spent behind the walls of heavily guarded mansions and in members-only clubs.

No wonder a book providing an insider's view on the matter has become an instant bestseller in Moscow.

The author, businesswoman Oksana Robsky, admits that the book - going by the English title "Casual" - is largely based on her own experience.

Its characters are women living in Moscow's most prestigious neighbourhood - Rublyovka.

The Rosman publishers sold 30,000 copies of the book in two weeks - as much as they had hoped to sell by the end of May.

Rosman's spokeswoman Natalya Dolgova told the BBC that most of the readers were women.

The book has drawn comparisons with the US hit series Sex and the City.

But apart from visiting luxury fitness clubs, massage parlours and bohemian parties its main character goes about a specifically Russian business - avenging the contract killing of her husband at the hands of gangsters.

The second of Mrs Robsky's three husbands was also murdered.

'Hard-working people'

Before writing the book, Mrs Robsky ran a female bodyguards agency called "Nikita", sold Asian furniture and designed uniforms for her neighbours' servants in the highly desirable village of Zhukovka - the creme de la creme of Rublyovka.

My masseuse lives on the lower ground floor of my house. She has strong hands and a thievish look, typical of people who live for tips. In her native Donetsk a masseuse's monthly salary is equal to the cost of two California rolls in the Slavyanskaya Hotel or my manicure

Excerpt from Casual

Her own mansion stands next to that of Mikhail Khodorkovsky, the jailed ex-boss of Russian oil giant Yukos. Even a very modest home in the area costs millions of dollars.

Asked how secure the residents of Rublyovka feel about their future, she replies: "Have you heard about Khodorkovsky? How secure do you think they are?"

But she rejects the image of the Russian rich living in luxury ghettos surrounded by a hostile population eager to plunder their homes at the first opportunity.

Mrs Robsky admits her story is largely autobiographical

"No, they are not isolated. They talk to their employees, parents, childhood friends, who live very different lives," she said.

She said the Russian elite - often accused of cynicism, brutality and extravagance - consisted of people "no better and no worse than other people, not just in Russia, but in the whole world".

"One thing that unites them is that they work hard. Middle-class people work from nine till six and then return to their families, beer and football, but these people seldom finish before 10 pm," she told the BBC by phone from her Mercedes.

Authenticity

This is not exactly the impression one might get from her book.

One character dyes her Yorkshire terrier's coat purple to match the colour of her favourite jacket. The characters chat about skiing vacations costing $1,700 a day and one even fakes a miscarriage to get an enormous allowance from her disloyal husband.

For the likes of Olezhek, with his metal teeth, $10m is the same as 10 kilos of bones for a stray dog

Excerpt from Casual

Some Russian critics have been quite caustic about the literary qualities of Casual.

The liberal Moskovskiye Novosti paper said the book's style was no match for its documentary value.

"Even the worst informed reader can guess who the prototypes were for certain characters. This is especially true of the scenes of romantic intimacy, which possess the power of rare authenticity," the newspaper says.

One of Russia's most popular film directors, Sergei Chliyants, says he will make a film based on the book, and the author herself might play the main role in it.